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Are All Surface Prep Standards Created Equal? Part 3


By Lee Wilson

In my previous two blog posts, I’ve taken a look at the ISO surface preparation standards, and contrasted them with the more thorough SSPC/NACE joint standards. The question this has brought us to—and that I’ll try to address in this final instalment—is: Why, when the joint standards supply so much more information, are specifiers still choosing the ISO 8501-1 standards for dry abrasive blasting without stating the SSPC/NACE standards as equivalents?

Now we have to look at the definition of what a standard actually is! The definition of a standard, according to ISO, is as follows: “A standard is a document that provides requirements, specifications, guidelines or characteristics that can be used consistently to ensure that materials, products, processes and services are fit for their purpose.”

As an inspector, I want clear and concise guidelines, without ambiguity and without contradiction, which allow me to execute a successful project without causing chaos whilst in the field. Whether the asset in question is an offshore installation, a maritime vessel or an oil refinery, even down to our transport infrastructure, it is in the field where disputes happen—and disputes can lead to major issues on any construction project.

© / kimtaro

It is in the field where disputes happen—and disputes can lead to major issues on any construction project.

A contractor on a project I was once involved in argued the case that there where slight stains in the blast to which the company he was representing had achieved. I personally disagreed and felt that that the stains were far from slight—so I asked him to define and quantify “slight!”

Now you can grasp where simple wording can cause chaos: It’s his opinion versus mine. Common sense ultimately prevailed, and a re-blast was carried out. However, the scenario in its entirety could have been prevented had a quantifiable measurement been put into the standard.

Why is this so important?

Surface Prep Prevents Failures

Well, like it or not, it is all about how clean the surface is before applying your protective coating. Some estimate that 60 to 85 percent of all premature failures can be attributed directly to inadequate surface preparation, regardless of whether you are applying the latest and greatest protective coating. If you have not cleaned the substrate, you can expect premature failure of your protective coating or a reduced service life at the very least.

Table of former joint standards

The ISO and SSPC/NACE joint standards were previously considered to be equivalent.

Therefore, you can see the importance of surface preparation and the endless debates about it that can ensue. My intention is to reduce this by trying to get a quantifiable measurement incorporated into the ISO standard. I believe that as the standard stands it is wide open to interpretation and potential abuse.

Another popular myth is that the ISO 8501-1 and the Joint NACE/SSPC Dry abrasive blasting standards are equivalents. I see this in tech papers, theses and also bounced around on social media debates by so-called industry experts. Let me clarify why this is no longer the case.

No Longer Equivalents

The standards where once deemed as equivalents; however, this was predominately due to the visual appearance of the standards.

This is no longer the case, and the standards are no longer deemed as equivalent by the relevant institutes. So, my friends, I would dissuade you from stating that the standards are equivalent on your projects. I would also sway you from specifying the same, as you would be incorrect in doing so.

I tried to learn why the standards are no longer equivalent, but I could not get a definitive answer from either institute—however, I do believe it is rather obvious. In my opinion, it is the lack of a quantitative measurement of allowed contamination on the substrate after blasting has been carried out. This also leaves me no option but to contemplate: If this is the case, should I believe that the ISO standard is in fact inferior to the joint NACE/SSPC surface preparation standards, with regard to quality assurance?

Some good food for thought!


Lee Wilson

Lee Wilson, CEng, FICorr, is a NACE Level 3-certified CIP Instructor, NACE Corrosion Specialist, NACE Protective Coating Specialist and Senior Corrosion Technologist, as well as an ICorr Level 3 Painting Inspector and Level 2 Insulation Inspector. The author of the best-selling Paint Inspector’s Field Guide, Lee was named one of JPCL Top Thinkers: The Clive Hare Honors in 2012. Contact Lee.



Tagged categories: Abrasive blasting; Certifications and standards; ISO; SSPC-SP 10; SSPC-SP 5; SSPC-SP 6; SSPC-SP 7; Surface preparation

Comment from Arthur Ruff, (2/6/2017, 9:18 AM)

The standards are not equal an ISO Sa 2 allows mill scale, SSPC SP 6 does not allow any mil scale and most crossover charts have them as an equal.

Comment from Lee Wilson, (2/6/2017, 10:37 AM)

Precisely my point Arthur

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